M. K., Y., P., S., D. M., V. and U. K., A. R. (2017) “A comparative study of epidural tramadol with epidural pentazocine for postoperativeanalgesia in patients undergoing lower abdominal surgeries”, International Journal of Basic & Clinical Pharmacology, 6(10), pp. 2441–2445. doi: 10.18203/2319-2003.ijbcp20174373.